1. Field of the Invention
The present invention relates to the application of coating constituents to form desired types of coatings on relatively large surface areas that characteristically are referred to as "traffic surfaces," typically roadway surfaces such as highways, streets, driveways, parking lots, runways, taxiways, and tarmacs that are of sufficient size to warrant the use of relatively large power operated machinery to dispense and mix coating constituents to form desired types of coatings, and to spread and apply the mixed constituents to form coatings of desired character that are intended to protect, restore and enhance traffic surface integrity.
More particularly, the present invention relates to a center-fed system for dispensing coating constituents onto a traffic surface, for mixing the dispensed constituents in situ on the traffic surface (to such extent may be needed), for spreading the mixed constituents, and for effecting a controlled application of the resulting coating by utilizing at least one set of rotary tools that extends beneath a wheeled support carriage, with the tools of each such set being connected to a separate, hollow, tubular stub shaft that is journaled for rotation relative to the carriage about the stub shaft's vertically extending center axis. In accordance with a feature of the present invention, at least a portion of the coating constituents that are to be applied to a traffic surface are dispensed onto the traffic surface as by being ducted through the hollow stub shaft(s) for discharge substantially centrally relative to the associated set(s) of rotating tools, whereby the tools are brought into engagement with the deposited constituents to effect desirable types of in situ mixing, spreading and application of the deposited constituents to the traffic surface.
2. Prior Art
In the present document, the term "traffic surface" is used in a generic sense to refer to a wide class of substantially horizontal surfaces such as highways, streets, driveways, parking lots, runways, taxiways, tarmacs, floors of large garages and industrial buildings, loading dock decks, and the like that need to be coated from time to time to protect, restore and enhance surface integrity.
Because traffic surfaces are exposed to wear and often to the effects of the elements, they are subject to deterioration and periodically require the application of coatings to protect, restore and enhance their integrity, and to thereby extend their useful lives. Some traffic surfaces should be coated when constructed, as by the application of a coating that seals exposed surfaces and thereby protects against water penetration that, in winter, can cause spalding or cracking. Many traffic surfaces require protective and reconditioning coatings periodically and/or after the surfaces have been subjected to a certain amount of use.
Due to the wide variety of materials that are used to form traffic surfaces, the wide range of uses to which traffic surfaces are subjected, and the many types of coating constituents that are available to protect against specific kinds of wear and deterioration, there has been a longstanding need for a highly versatile system for dispensing, mixing, spreading and applying coatings to traffic surfaces. The need has been particularly pressing with respect to the protective coating of traffic surfaces of large area such as highways, airport runways, bridge roadways, and the like where manual dispensing, mixing, spreading and application of coating constituents is impractical.
While a variety of proposals have been made for apparatus to dispense, mix, spread and coat large traffic surfaces, most prior proposals have been characterized by drawbacks such as a lack of versatility of the apparatus to dispense, mix, spread and apply coating constituents of a wide range of kinds and types, and/or a lack of adjustability to enable coating applications to be made that differ in desired ways such as thickness and the degree to which the resulting coating conforms to the shape of the surface being coated (e.g., whether the coating tends to smooth or diminish surface irregularities). Indeed, the problems that are associated with efforts to provide a highly versatile traffic surface coating system have been deemed to be so extensive in character that it has become standard practice to design and build traffic surface coating apparatus such that it is intended to apply only a limited selection of coating constituents, with the apparatus being designed for use on only selected types of traffic surfaces.
Further and significant limitations of many prior applicator proposals reside in such drawbacks as 1) their inability to effectively dispense and admix in situ materials such as epoxy substances, fibrous, beaded, or heavy particulates, 2) their inability to effectively dispense and admix in situ quick-setting soluble substances to form uniform slurry compositions, and/or 3) their inability to properly spread and apply resulting coatings.
3. The Referenced Parent Cases
While the referenced Parent Cases address certain of the foregoing and other drawbacks of prior proposals as by providing novel and improved systems that are well suited for use in a wide variety of coating application situations, the approach that has tended to be employed in carrying out the preferred practice of the inventions of the referenced Parent Cases is one of applying coating constituents to traffic surfaces at locations that are spaced from where sets of rotary tools are operating. Typically, prior proposals call for one or more sets of rotary tools to be moved forwardly along paths of travel in order to bring the rotary tools into engagement with deposited coating constituents to effect such functions as the mixing of constituents, and the spreading and application of the resulting coating.
Not specifically addressed by the inventions of the referenced Parent Cases are certain advantages that have been found to result from taking a somewhat different approach than is described above, namely the approach of dispensing selected coating constituents at a central location or at central locations about which one or more sets of rotary tools are moving. The system of the present invention provides such advantages, as will become apparent from the discussion that follows. Thus, while the system of the present invention may, in some modes of practice, make use of a number of features that are disclosed in the referenced Parent Cases, the system of the present invention provides improved method and apparatus features that extend beyond the scope of the referenced Parent Cases.